1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to providing a projection display apparatus an more particularly, to providing a projection display apparatus enhancing image quality.
2. Description of the Related Art
Liquid crystal displays, plasma display panels, projection display apparatuses such as projectors, and the like, are being used as apparatuses for displaying large-sized, high-quality images. Projection display apparatuses enlarge small-sized images and project the images onto large-sized screens. Recently, lamps have been used as light sources of projection display apparatuses.
However, lamps being used as light sources have short life spans and produce a lot of heat. Further, when lamps are used as light sources, the definition of a displayed image is lower, compared to when other types of light sources are used. For these reasons, efforts have been being made to develop alternative light sources capable of being used instead of lamps in projection display apparatuses and the like.
A laser beam has high directionality, making it easy to predict a change in a path of a laser beam due to reflection and/or refraction. For this reason, lasers are being used as alternative light sources for projection display apparatuses and the like. In the case of using a laser as a light source, it is possible to make a wide reproducible color range and to obtain clear images.
However, laser beams maintain the same temporal and spatial phases, resulting in the coherence of laser beams. The coherence of laser beams causes a speckle pattern to be produced on a screen. The speckle pattern appears illuminate spots on the screen. Therefore, the speckle pattern degrades the image quality, contrast, and resolution of images, and particularly of enlarged images.
A method of sequentially irradiating red, green, and blue beams to an image display element, which modulates beams corresponding to image information, has been used. However, the above-mentioned method reduces light utilization efficiency. For this reason, a method of simultaneously irradiating red, green, and blue beams to an image display elements has been developed.